Method and apparatus for performing refresh operations in high-density memories

Abstract

A method for performing refresh operations is disclosed. In response to a completion of a memory operation, a determination is made whether or not a refresh backlog count is greater than a first predetermined value. In a determination that the refresh backlog count is greater than the first predetermined value, a refresh operation is performed as soon as possible. In a determination that the refresh backlog count is not greater than the first predetermined value, a refresh operation is performed after a delay of an idle count value.

What is claimed is: 
     
       1. A method for performing refresh operations, said method comprising:
 in response to a completion of a memory operation, determining whether or not a refresh backlog count is greater than a first predetermined value; 
 in a determination that said refresh backlog count is greater than said first predetermined value, performing a refresh operation as soon as possible; and 
 in a determination that said refresh backlog count is not greater than said first predetermined value, performing a refresh operation after a delay of an idle count value. 
 
     
     
       2. The method of  claim 1 , wherein said first predetermined value is 7. 
     
     
       3. The method of  claim 1 , wherein said idle count value is negatively proportional to said refresh backlog count. 
     
     
       4. The method of  claim 3 , wherein said second predetermined value is 3. 
     
     
       5. The method of  claim 1 , wherein said method further includes
 determining whether or not said refresh backlog count is less than a second predetermined value; 
 in a determination that said refresh backlog count is less than said second predetermined value, performing a refresh operation after a delay of a maximum idle count value.